/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.sun.org.apache.xerces.internal.dom;

import com.sun.org.apache.xerces.internal.impl.RevalidationHandler;
import com.sun.org.apache.xerces.internal.parsers.DOMParserImpl;
import com.sun.org.apache.xerces.internal.parsers.DTDConfiguration;
import com.sun.org.apache.xerces.internal.parsers.XIncludeAwareParserConfiguration;
import com.sun.org.apache.xerces.internal.util.XMLChar;
import com.sun.org.apache.xerces.internal.utils.ObjectFactory;
import com.sun.org.apache.xerces.internal.xni.grammars.XMLGrammarDescription;
import com.sun.org.apache.xml.internal.serialize.DOMSerializerImpl;
import org.w3c.dom.DOMException;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.ls.LSParser;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSInput;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;

/**
 * The DOMImplementation class is description of a particular
 * implementation of the Document Object Model. As such its data is
 * static, shared by all instances of this implementation.
 * <P>
 * The DOM API requires that it be a real object rather than static
 * methods. However, there's nothing that says it can't be a singleton,
 * so that's how I've implemented it.
 * <P>
 * This particular class, along with CoreDocumentImpl, supports the DOM
 * Core and Load/Save (Experimental). Optional modules are supported by
 * the more complete DOMImplementation class along with DocumentImpl.
 *
 * @version $Id: CoreDOMImplementationImpl.java,v 1.6 2010-11-01 04:39:37 joehw Exp $
 * @xerces.internal
 * @since PR-DOM-Level-1-19980818.
 */
public class CoreDOMImplementationImpl
    implements DOMImplementation, DOMImplementationLS {
  //
  // Data
  //

  // validators pool
  private static final int SIZE = 2;
  private RevalidationHandler validators[] = new RevalidationHandler[SIZE];

  private RevalidationHandler dtdValidators[] = new RevalidationHandler[SIZE];
  private int freeValidatorIndex = -1;
  private int freeDTDValidatorIndex = -1;
  private int currentSize = SIZE;

  // Document and doctype counter.  Used to assign order to documents and
  // doctypes without owners, on an demand basis.   Used for
  // compareDocumentPosition
  private int docAndDoctypeCounter = 0;

  // static
  /**
   * Dom implementation singleton.
   */
  static CoreDOMImplementationImpl singleton =
      new CoreDOMImplementationImpl();
  //
  // Public methods
  //

  /**
   * NON-DOM: Obtain and return the single shared object
   */
  public static DOMImplementation getDOMImplementation() {
    return singleton;
  }
  //
  // DOMImplementation methods
  //

  /**
   * Test if the DOM implementation supports a specific "feature" --
   * currently meaning language and level thereof.
   *
   * @param feature The package name of the feature to test. In Level 1, supported values are "HTML"
   * and "XML" (case-insensitive). At this writing, com.sun.org.apache.xerces.internal.dom supports
   * only XML.
   * @param version The version number of the feature being tested. This is interpreted as "Version
   * of the DOM API supported for the specified Feature", and in Level 1 should be "1.0"
   * @return true iff this implementation is compatable with the specified feature and version.
   */
  public boolean hasFeature(String feature, String version) {

    boolean anyVersion = version == null || version.length() == 0;

    // check if Xalan implementation is around and if yes report true for supporting
    // XPath API
    // if a plus sign "+" is prepended to any feature name, implementations
    // are considered in which the specified feature may not be directly
    // castable DOMImplementation.getFeature(feature, version). Without a
    // plus, only features whose interfaces are directly castable are considered.
    if ((feature.equalsIgnoreCase("+XPath"))
        && (anyVersion || version.equals("3.0"))) {
      try {
        Class xpathClass = ObjectFactory.findProviderClass(
            "com.sun.org.apache.xpath.internal.domapi.XPathEvaluatorImpl", true);

        // Check if the DOM XPath implementation implements
        // the interface org.w3c.dom.XPathEvaluator
        Class interfaces[] = xpathClass.getInterfaces();
        for (int i = 0; i < interfaces.length; i++) {
          if (interfaces[i].getName().equals(
              "org.w3c.dom.xpath.XPathEvaluator")) {
            return true;
          }
        }
      } catch (Exception e) {
        return false;
      }
      return true;
    }
    if (feature.startsWith("+")) {
      feature = feature.substring(1);
    }
    return (
        feature.equalsIgnoreCase("Core")
            && (anyVersion
            || version.equals("1.0")
            || version.equals("2.0")
            || version.equals("3.0")))
        || (feature.equalsIgnoreCase("XML")
        && (anyVersion
        || version.equals("1.0")
        || version.equals("2.0")
        || version.equals("3.0")))
        || (feature.equalsIgnoreCase("LS")
        && (anyVersion || version.equals("3.0")));
  } // hasFeature(String,String):boolean


  /**
   * Introduced in DOM Level 2. <p>
   *
   * Creates an empty DocumentType node.
   *
   * @param qualifiedName The qualified name of the document type to be created.
   * @param publicID The document type public identifier.
   * @param systemID The document type system identifier.
   * @since WD-DOM-Level-2-19990923
   */
  public DocumentType createDocumentType(String qualifiedName,
      String publicID, String systemID) {
    // REVISIT: this might allow creation of invalid name for DOCTYPE
    //          xmlns prefix.
    //          also there is no way for a user to turn off error checking.
    checkQName(qualifiedName);
    return new DocumentTypeImpl(null, qualifiedName, publicID, systemID);
  }

  final void checkQName(String qname) {
    int index = qname.indexOf(':');
    int lastIndex = qname.lastIndexOf(':');
    int length = qname.length();

    // it is an error for NCName to have more than one ':'
    // check if it is valid QName [Namespace in XML production 6]
    if (index == 0 || index == length - 1 || lastIndex != index) {
      String msg =
          DOMMessageFormatter.formatMessage(
              DOMMessageFormatter.DOM_DOMAIN,
              "NAMESPACE_ERR",
              null);
      throw new DOMException(DOMException.NAMESPACE_ERR, msg);
    }
    int start = 0;
    // Namespace in XML production [6]
    if (index > 0) {
      // check that prefix is NCName
      if (!XMLChar.isNCNameStart(qname.charAt(start))) {
        String msg =
            DOMMessageFormatter.formatMessage(
                DOMMessageFormatter.DOM_DOMAIN,
                "INVALID_CHARACTER_ERR",
                null);
        throw new DOMException(DOMException.INVALID_CHARACTER_ERR, msg);
      }
      for (int i = 1; i < index; i++) {
        if (!XMLChar.isNCName(qname.charAt(i))) {
          String msg =
              DOMMessageFormatter.formatMessage(
                  DOMMessageFormatter.DOM_DOMAIN,
                  "INVALID_CHARACTER_ERR",
                  null);
          throw new DOMException(
              DOMException.INVALID_CHARACTER_ERR,
              msg);
        }
      }
      start = index + 1;
    }

    // check local part
    if (!XMLChar.isNCNameStart(qname.charAt(start))) {
      // REVISIT: add qname parameter to the message
      String msg =
          DOMMessageFormatter.formatMessage(
              DOMMessageFormatter.DOM_DOMAIN,
              "INVALID_CHARACTER_ERR",
              null);
      throw new DOMException(DOMException.INVALID_CHARACTER_ERR, msg);
    }
    for (int i = start + 1; i < length; i++) {
      if (!XMLChar.isNCName(qname.charAt(i))) {
        String msg =
            DOMMessageFormatter.formatMessage(
                DOMMessageFormatter.DOM_DOMAIN,
                "INVALID_CHARACTER_ERR",
                null);
        throw new DOMException(DOMException.INVALID_CHARACTER_ERR, msg);
      }
    }
  }


  /**
   * Introduced in DOM Level 2. <p>
   *
   * Creates an XML Document object of the specified type with its document
   * element.
   *
   * @param namespaceURI The namespace URI of the document element to create, or null.
   * @param qualifiedName The qualified name of the document element to create.
   * @param doctype The type of document to be created or null.<p>
   *
   * When doctype is not null, its Node.ownerDocument attribute is set to the document being
   * created.
   * @return Document        A new Document object.
   * @throws DOMException WRONG_DOCUMENT_ERR: Raised if doctype has already been used with a
   * different document.
   * @since WD-DOM-Level-2-19990923
   */
  public Document createDocument(
      String namespaceURI,
      String qualifiedName,
      DocumentType doctype)
      throws DOMException {
    if (doctype != null && doctype.getOwnerDocument() != null) {
      String msg =
          DOMMessageFormatter.formatMessage(
              DOMMessageFormatter.DOM_DOMAIN,
              "WRONG_DOCUMENT_ERR",
              null);
      throw new DOMException(DOMException.WRONG_DOCUMENT_ERR, msg);
    }
    CoreDocumentImpl doc = new CoreDocumentImpl(doctype);
    Element e = doc.createElementNS(namespaceURI, qualifiedName);
    doc.appendChild(e);
    return doc;
  }

  /**
   * DOM Level 3 WD - Experimental.
   */
  public Object getFeature(String feature, String version) {
    if (singleton.hasFeature(feature, version)) {
      if ((feature.equalsIgnoreCase("+XPath"))) {
        try {
          Class xpathClass = ObjectFactory.findProviderClass(
              "com.sun.org.apache.xpath.internal.domapi.XPathEvaluatorImpl", true);
          // Check if the DOM XPath implementation implements
          // the interface org.w3c.dom.XPathEvaluator
          Class interfaces[] = xpathClass.getInterfaces();
          for (int i = 0; i < interfaces.length; i++) {
            if (interfaces[i].getName().equals(
                "org.w3c.dom.xpath.XPathEvaluator")) {
              return xpathClass.newInstance();
            }
          }
        } catch (Exception e) {
          return null;
        }
      } else {
        return singleton;
      }
    }
    return null;
  }

  // DOM L3 LS

  /**
   * DOM Level 3 LS CR - Experimental.
   * Create a new <code>LSParser</code>. The newly constructed parser may
   * then be configured by means of its <code>DOMConfiguration</code>
   * object, and used to parse documents by means of its <code>parse</code>
   * method.
   *
   * @param mode The <code>mode</code> argument is either <code>MODE_SYNCHRONOUS</code> or
   * <code>MODE_ASYNCHRONOUS</code>, if <code>mode</code> is <code>MODE_SYNCHRONOUS</code> then the
   * <code>LSParser</code> that is created will operate in synchronous mode, if it's
   * <code>MODE_ASYNCHRONOUS</code> then the <code>LSParser</code> that is created will operate in
   * asynchronous mode.
   * @param schemaType An absolute URI representing the type of the schema language used during the
   * load of a <code>Document</code> using the newly created <code>LSParser</code>. Note that no
   * lexical checking is done on the absolute URI. In order to create a <code>LSParser</code> for
   * any kind of schema types (i.e. the LSParser will be free to use any schema found), use the
   * value <code>null</code>. <p ><b>Note:</b>    For W3C XML Schema [<a
   * href='http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/'>XML Schema Part 1</a>] ,
   * applications must use the value <code>"http://www.w3.org/2001/XMLSchema"</code>. For XML DTD
   * [<a href='http://www.w3.org/TR/2000/REC-xml-20001006'>XML 1.0</a>], applications must use the
   * value <code>"http://www.w3.org/TR/REC-xml"</code>. Other Schema languages are outside the scope
   * of the W3C and therefore should recommend an absolute URI in order to use this method.
   * @return The newly created <code>LSParser</code> object. This <code>LSParser</code> is either
   * synchronous or asynchronous depending on the value of the <code>mode</code> argument. <p
   * ><b>Note:</b>    By default, the newly created <code>LSParser</code> does not contain a
   * <code>DOMErrorHandler</code>, i.e. the value of the "<a href='http://www.w3.org/TR/2003/WD-DOM-Level-3-Core-20030609/core.html#parameter-error-handler'>
   * error-handler</a>" configuration parameter is <code>null</code>. However, implementations may
   * provide a default error handler at creation time. In that case, the initial value of the
   * <code>"error-handler"</code> configuration parameter on the new created <code>LSParser</code>
   * contains a reference to the default error handler.
   * @throws DOMException NOT_SUPPORTED_ERR: Raised if the requested mode or schema type is not
   * supported.
   */
  public LSParser createLSParser(short mode, String schemaType)
      throws DOMException {
    if (mode != DOMImplementationLS.MODE_SYNCHRONOUS || (schemaType != null &&
        !"http://www.w3.org/2001/XMLSchema".equals(schemaType) &&
        !"http://www.w3.org/TR/REC-xml".equals(schemaType))) {
      String msg =
          DOMMessageFormatter.formatMessage(
              DOMMessageFormatter.DOM_DOMAIN,
              "NOT_SUPPORTED_ERR",
              null);
      throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
    }
    if (schemaType != null
        && schemaType.equals("http://www.w3.org/TR/REC-xml")) {
      return new DOMParserImpl(new DTDConfiguration(),
          schemaType);
    } else {
      // create default parser configuration validating against XMLSchemas
      return new DOMParserImpl(new XIncludeAwareParserConfiguration(),
          schemaType);
    }
  }

  /**
   * DOM Level 3 LS CR - Experimental.
   * Create a new <code>LSSerializer</code> object.
   *
   * @return The newly created <code>LSSerializer</code> object. <p ><b>Note:</b>    By default, the
   * newly created <code>LSSerializer</code> has no <code>DOMErrorHandler</code>, i.e. the value of
   * the <code>"error-handler"</code> configuration parameter is <code>null</code>. However,
   * implementations may provide a default error handler at creation time. In that case, the initial
   * value of the <code>"error-handler"</code> configuration parameter on the new created
   * <code>LSSerializer</code> contains a reference to the default error handler.
   */
  public LSSerializer createLSSerializer() {
    return new DOMSerializerImpl();
  }

  /**
   * DOM Level 3 LS CR - Experimental.
   * Create a new empty input source.
   *
   * @return The newly created input object.
   */
  public LSInput createLSInput() {
    return new DOMInputImpl();
  }

  //
  // Protected methods
  //

  /**
   * NON-DOM: retrieve validator.
   */
  synchronized RevalidationHandler getValidator(String schemaType) {
    // REVISIT: implement retrieving DTD validator
    if (schemaType == XMLGrammarDescription.XML_SCHEMA) {
      // create new validator - we should not attempt
      // to restrict the number of validation handlers being
      // requested
      if (freeValidatorIndex < 0) {
        return (RevalidationHandler) (ObjectFactory
            .newInstance(
                "com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator",
                ObjectFactory.findClassLoader(),
                true));
      }
      // return first available validator
      RevalidationHandler val = validators[freeValidatorIndex];
      validators[freeValidatorIndex--] = null;
      return val;
    } else if (schemaType == XMLGrammarDescription.XML_DTD) {
      if (freeDTDValidatorIndex < 0) {
        return (RevalidationHandler) (ObjectFactory
            .newInstance(
                "com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator",
                ObjectFactory.findClassLoader(),
                true));
      }
      // return first available validator
      RevalidationHandler val = dtdValidators[freeDTDValidatorIndex];
      dtdValidators[freeDTDValidatorIndex--] = null;
      return val;
    }
    return null;
  }

  /**
   * NON-DOM: release validator
   */
  synchronized void releaseValidator(String schemaType,
      RevalidationHandler validator) {
    // REVISIT: implement support for DTD validators as well
    if (schemaType == XMLGrammarDescription.XML_SCHEMA) {
      ++freeValidatorIndex;
      if (validators.length == freeValidatorIndex) {
        // resize size of the validators
        currentSize += SIZE;
        RevalidationHandler newarray[] = new RevalidationHandler[currentSize];
        System.arraycopy(validators, 0, newarray, 0, validators.length);
        validators = newarray;
      }
      validators[freeValidatorIndex] = validator;
    } else if (schemaType == XMLGrammarDescription.XML_DTD) {
      ++freeDTDValidatorIndex;
      if (dtdValidators.length == freeDTDValidatorIndex) {
        // resize size of the validators
        currentSize += SIZE;
        RevalidationHandler newarray[] = new RevalidationHandler[currentSize];
        System.arraycopy(dtdValidators, 0, newarray, 0, dtdValidators.length);
        dtdValidators = newarray;
      }
      dtdValidators[freeDTDValidatorIndex] = validator;
    }
  }

  /**
   * NON-DOM:  increment document/doctype counter
   */
  protected synchronized int assignDocumentNumber() {
    return ++docAndDoctypeCounter;
  }

  /**
   * NON-DOM:  increment document/doctype counter
   */
  protected synchronized int assignDocTypeNumber() {
    return ++docAndDoctypeCounter;
  }

  /* DOM Level 3 LS CR - Experimental.
   *
   * Create a new empty output destination object where
   * <code>LSOutput.characterStream</code>,
   * <code>LSOutput.byteStream</code>, <code>LSOutput.systemId</code>,
   * <code>LSOutput.encoding</code> are null.

   * @return  The newly created output object.
   */
  public LSOutput createLSOutput() {
    return new DOMOutputImpl();
  }

} // class DOMImplementationImpl
